Solvent and fuel containing same



Eatemei May 5, 1942 UNITED STATES PATENT OFFIE SOLVENT AND FUEL CONTAINING SAME poration of Ohio No Drawing. Application March 17, 1939, Serial No. 262,504

6 Claims.

This invention relates, as indicated, to a new solvent, and also to such fuel as is consumed by internal combustion engines which has added thereto my new solvent in order to increase the efliciency of operation of the engine. This application is in part a continuation of applicants co-pending application Serial No. 107,228, filed October 23, 1936. This application is also a continuation-impart of my copending application, Serial No. 737,070, filed July 26, 1934.

It is a fact, generally known, that so-called carbon" deposits form on the cylinder walls, pistons, valves, etc., making for inefficient operation of the engine due to such consequences as:

1. Carbon n piston head and cylinder head increases the knock susceptibility of a motor.

2. Carbon on piston head and cylinder head causes higher temperatures to be maintained, sometimes resulting in pre-ignition.

3. Carbon around the spark plug frequently causes shorting of the plug, which means that the cylinder will not fire.

4. Carbon around and behind piston rings causes the rings to set, lowering compression, increasing oil consumption and decreasing power.

5. Carbon around valve seats and valve stems will not allow the valves to close properly, which causes decreased compression, burning of the valves, loss of power, etc.

The formation of these deposits, which consist of carbon and other solids bound together by gummy binders, occurs whenever any of the ordinary fuels is used and necessitates more frequent engine overhauls than would otherwise be required, such overhauls being a source of continual annoyance and expense.

Midgley, in Patent No. 1,668,022 has disclosed the use of tetra-ethyl lead and a. volatile bromide compound in an internal combustion engine fuel for the purpose of suppressing engineknock, the bromide compound in certain respects inhibiting the deleterious effects of lead deposits, and such a mixture is now commonly employed. However, the combustion of the fuel thus improved gives rise to other problems, the solution of which is among the objects of this invention.

It has been discovered that these carbon deposits resulting from the combustion of internal combustion engine fuels contain a binder which has two principal components: (1) condensed and/or polymerized hydrocarbons and (2) more or less oxidized condensed and/or polymerized hydrocarbons. I have found that the best solvents for component (1) are not the best solvents for component (2) and that the best solvent for the binder is a combination of the two types of solvents respectively best suited to dissolve the separate components of the binder. For addition to the fuel, it is obvious that solvents must be found which are mutually compatible, soluble or miscible in the fuel, or capable of forming a stable form of suspension or emulsion and which will dissolve the two sorts of gummy binders previously referred to. I

It is, therefore, among the objects of my invention to provide a new solvent which will be effective in the removal of carbon deposits of the sort found in internal combustion engines by acting upon the gummy binders in the deposit composition.

It is also among the objects of this invention to provide an engine fuel suitable for consumption by internal combustion engines, and which has mixed therewith my improved solvent which will inhibit the formation of these carbon deposits and aid in the removal of any already formed.

Another object of this invention is to provide an engine fuel having all of the above-named desirable characteristics and which, in addition, has the further effect of aiding in the carrying off of the metal when such compounds as lead tetra-ethyl are utilized in the fuel, this composition being non-corrosive in use.

Other objects of the invention will appear as the description proceeds.

To the accomplishment of the foregoing and related ends, said invention then consists of the means hereinafter fully described and particularly pointed out in the claims.

The following description sets forth in detail certain approved combinations of ingredients embodying my invention, such disclosed means constituting, however, but certain of various forms in which the principle of the invention may be used.

Broadly stated, this invention comprises a new solvent for condensed and/or polymerized organic materials and especially for such materials containing a combination of condensed and/or polymerized hydrocarbons and condensed and/or polymerized oxidized hydrocarbons, said solvent containing a mixture of at least one each of certain halogenated oxygen-free organic compounds and at least one each of certain oxygenbearing organic compounds. of these latter compounds some are more effective in some services if halo enated and more effective in other services and under different conditions is unhalogenated.

An important use for my new solvent is in dissolving the binder of carbon deposits usually found in the combustion chambers of internal combustion engines. For this reason the succeeding paragraphs are largely a description of such use and especially of engine fuels designed to have this and other desirable effects. My new solvent may, however, be utilized whenever deposits of the general type described are encountered.

As is hereinafter more particularly pointed out, the above defined components of the solvent comprising th.s invention will preferably and for best results have certain physical and chemical characteristics which especially adapt Such components and the solvent containing the same for use in conjunction with the principal types of engine fuel in common use today.

The components of the solvent should be of low volatility, i. e., with a vapor pressure at a temperature of 170 C. of below atmospheric and capable of boiling at atmospheric pressure without substantial decompos tion. In one embodiment of my invention now in commercial use. one component of my new solvent has a vapor pressure less than atmospheric at a temperature above 300"v C. A mixture of two components, one with a vapor pressure a little below atmospheric at 170 C. and the other with a vapor pressure a little below atmospheric at 350 C., has proven highly satisfactory.

Oxygen free component I have found that the halogenated oxygen-free densed ring type will be found sufficiently stable for the purposes above defined. Poly nuclear aromatic compounds (that is, those containing more than one ring) of the non-condensed ring type are thus-the more desirable of the stable aromatic compounds which are available for use.

As hereinafter pointed out, certain of the aliphatic compounds are likewise suitable although, in general, the aliphatic compounds will be found to be less stable than the type of aromatic compounds above referred to which is suitable for use.

In the case of the halogenated aromatic oxygen-free compounds, it is preferable that the halogen be attached to a carbon atom of the benzenoid ring. These latter compounds are usually more desirable because of their non-corrosive character and general stability.

The halogenated oxygen-free organic compounds as noted may be either:

A. Aliphatic, such as halogenated:

I. Hydrocarbons,

Notably, those containing from four to ten carbon atoms, e. g.:

Fluorinated hexane Fluorinated octane Fluorinated decane II. Amines Primary, secondary and tertiary,-

spouses or the more generally preferable:

2B. Cyclic compounds, such as halogenated:

' I. Benzene and related compounds such as:

' (1) Halogenated benzene, e. g.:

The dicblorbenzenes, notably the ortho compound The ortho-dibrom benzenes The fluorinated benzenes (2) Halogenated derivatives of benzene such as:

(a) Halogenated homologs benzene, e. g.:

Mono-chlor xylene Mono-chlor cymene' Ethyl mono-chlor benzenes Propyl mono-chlor benzenes Di-ethyl mono-chlor benzenes Ethyl dichlor benzenes Propyl dichlor benzenes Di-ethyl dichlor benzenes (b) Halogenated amino derivatives of benzene, e. g.:

Chlorinated aniline Mono-chlor aniline (preferably the ortho-compound) Mono-chlor di-methyl aniline Chlorinated toluidines Chlorinated xylidines Chlorinated diphenylamine (c) Halogenated hydrobenzenes,

Hydrogenated dichlor benzenes Dichlorhexahydrobenzene (Dichlor cyclohexane) (3) Aromatic nitriles, e. g., chlorinated phenyl nitrile II. Polyphenyls, and related compounds, including diphenyl, diphenyl benzenes, etc., such as,

(1) Chlorinated diphenyl, e. g.:

'Mono-chlor diphenyls Di-chlor diphenyls Tri-chlor diphenyls (2) Brominated diphenyl, e. g., the

mono-brom diphenyl (3) Fluorinated diphenyl (4) Halogenated derivatives of diphenyl, such as,

(a) Halogenated homologs of diphenyl, e. g.:

Chlorinated methyl diphenyls Chlorinated ethyl diphenyls (b) Halogenated amino derivatives of diphenyl, e. g.:

Chlorinated amino-diphenyls Chlorinated amino methyl diphenyls (c) Halogenated hydrodiphenyls,

Chlorinated phenyl hexahydrobenzene Chlorinated dodecahydrodiphenyl IV. Bridged ring compounds, such as the terpenes and related compounds, and their derivatives, e. g., chlorinated pinene. V. Heterocyclic compounds, such as pyridine, quinoline, pyrrole, thiophene, and derivatives of them, e. g., mono-chlorpyridine.

Very satisfactory results may be obtained when two or more diflerent halogens are present in the same molecule, orthobrom-chlor benzene, ethylorthobrom chlor benzene, and the fluorinated chlorine compounds being good examples of such compounds. If the aromatic compounds have been alkylated they are often especially effective.

As a matter of convenience, the halogenated diphenvls and substituted diphenyls, as well as halogenated substituted benzenes where two or more phenyl groups are directly linked, may be inclusively referred to as halogenated polyphenyls.

Some of the best examples of the aromatic solvents are:

Oxygen-l)earz1zgcomponent I have found that of the entire class of oxygen bearing organic compounds usable as a component of my new solvent, as above defined, the halogenated compounds and preferably those of the aromatic series are generally superior solvents for the oxidized polymerized hydrocarbon deposit, and that these solvents may .be used in conjunction with the solvents for the unoxidized condensed and/or polymerized hydrocarbon deposit, also being compatible with the fuel. Here again, compounds of the aromatic series with the halogen attached to the ring are favored. However, a certain number of the oxygen-bearing aliphatic compounds have been found to be very effective.

The oxygen-bearing components may, for convenience, be classified as follows:

I. Aliphatic, or carbon chain type Oxygen-bearing derivatives of:

A. Hydrocarbons of the parafiin series, B. Hydrocarbons of the olefine series and C. Hydrocarbons of the acetylene series,

(b) Other types such 'as iurfuralJuran and its derivatives and derivatives of thiophene, pyrrole, etc.

The oxygen-bearing derivatives of the foregoing compounds may also be classified according to the nature of the attachment of the oxygen to the molecule, viz:

I. Directly attached to one or more carbon atoms, as in the case of:

(1') Ethers and analogous compounds (2') Compounds containing the radicle, such as alcohols and other derivatives of carbinol (including phenols, cresols, naphthols etc.)

(3') Compounds containing the carbonyl radicle, such as amides, aldehydes, ketones, organic acids, esters and salts of organic acids, thio-acids and esters of thio-acids Compounds in which oxygen forms a part of the ring structure, e. g. furan and its derivatives, etc.

Compounds with inorganic radicle where the oxygen is directly attached to carbon atom Arsenite Hypochlorite Phosphite Thiophosphate i Thiophosphite p-Hydroxylamines II. Indirectly attached through the means of some other atom, i. e., in the form of an inorganic radicle, e. g.:

Arsenate Chlorate Chlorite Cyanate a-Hydroxylamine Nitrate Nitrite Nitro Nitroso Oxime Perchlorate Phosphate Sulphate Sulphite Sulphinic acid Sulphone Sulphonic acid Sulphoxide Thio-sulphate The iollowing table indicates some of the comeight atoms oi halogen permolecule. Chlopounds which are especially suitable, halogem rinated diphenyl ether which contains about six ated or unhalogenated, as the case may be: atoms of chlorine per molecule, and has preter- Oraantc ozwen compounds Ring compounds Unhalogenated Haiogenated Ph la 4 a:

sac

Phenol O-chlor henoi a-Naphthol Mon or a-naphthol Amino eno Butyl l "i "'Far acids" (preferably refined by distillation) Alcohols Benzyl alcohol Chlorhonzyl alcohols Phenyl ethyl alcohol Home ()lesirable because or a on p Benzaldehyde Ketones Benzo henone Mono-chlor benzophenone Phony tolylketones Dinaphthyl kemne Amides and substituted amides Benzamide Acetanilide Stearanllide Add! Ph litt ids h l a 0111 n l a acid on ayec e.g.penyaceo orpcnyacec E m acid Chlor-salioyclic acid a re Phenyacetate Ethyl chlorbenzoates Phen carbonate Butyl cblorbenzoates Ethy oenzoate Dl-ethyl chlorphthalates Butyl :acnzoate Dibutyl chlorphthalates Di-ethyl phthalate Ethyl and butyl esters of chlorphenyl Dibutyl phthalate acetic acid Ethy and butylesters of phcnyl acetic ac Methyl salicylate Moth lchlor salicylates s m Benzyl acetate Chlor nzyl acetates Pyridine acetate Quinoline acetate Aniline stearate Ethers Diphenyl ether Chlorinated diphenyl ether Phony] ethyl ether Chlo henyl ethyl ethers Dixon lether Chlo ated dixengl ether Dina thyl ether Chlorinated ding? thyl ether Alky ated diphenyl ether Alkylated chlor iphenyl ether Non-aromatic oxygen-bearing organic ring compounds Naphthenic acids Chlorinated cyclohexanoi Esters oi naphthenic acids Oxygen-bearing heterccycllo compounds (I) Furane and derivatives, e. g.

Esters oi pyromucic acid (inmates), Furiuryl a echo] and esters oi it, e. g. i'urfuryl acetate,

(2) Oxygen bearing derivatives oi thiophene and pyrrole, a. g., esters of thiophene carboxylic acids and esters of pyrrole carbcxylic acids.

ably been purified by vacuum distillation or chain other means, is one of the most desirable solvents p u Unhahgenmd Hamgenated of this class. This solvent boils at a temperature above 300 C. without appreciable decom- Alcohols Oct 18160110] Fluoflnsted my] alcohol position. (See my co-pending application No.

gec yl lalariohlol1 gluorinateeg ilecyllahlzohlllilI 3; 311 b0 ted 1 f a 0 m Bury 0 e a ve enumera c asses 0 oxygen- Estm Cety alcohol Fluorlnated oetyl alcohol hearing compounds, the aromatic compounds are ?E5 :& Methyl dichlor meme generally preferred and particularly the aromatic Hydroxy-amines ethers and ketones. Another preferred class of compounds is that in which oxygen forms a part Ethm 5 of a ring structure.

3 2;} Since, in general, aromatic compounds con- Ketone taining multiple ring structures of the condensed giffil g izggg type such as naphthalene, anthracene, phenanmwtylketone v threne, etc. (that is, of the type in which certain Acids .Lauflc acid carbon atoms are contained in or common to two rings) are more easily oxidized, and, therefore,

A good example of a solvent of the oxygenbearing class is chlorinated diphenyl ether, containing an average of from about three to about less stable than the non-condensed" multiplering type in which no. carbon atoms are thus shared, the latter type is to be preferred. Polynuclear aromatic compounds (that is, those containing more than one ring) of the non-condensed type are thus the more desirable of such aromatic compounds.

Preferred combinations to make up my new solvent include:

About 25% to 75% of o-dichlor benzene, ethyl dichlor benzenes, or ethyl chlor benzenes with one or more of the following:

The chlorinated diphenyl oxide compounds referred to above are compounds containing an average number of chlorine atoms that indicated. 1

Of the specific compounds mentioned in this application all are more or less eifective carbon binder solvents when used individually, although the highest efliciency is obtained with combinations as explained above. 'The individual examples of the immediately preceding list are among the best of the compounds which may be utilized by themselves.

Chlorine, bromine, and fluorine are the halo gens most desirable in both the oxygen-free and oxygen-containing compounds, fluorine forming particularly stable compounds which are no long-. er s diflicult to prepare as formerly. Methods of preparing fluorine compounds which will be found satisfactory for use in my solvent are described, for instance, in U. S. Patent No. 2,013,000, Example IV, and in U. S. Patent No. 2,013,050, Example X. My invention, of course, is not to be considered as involving any particular method of preparation of the components nor is it intended to be limited by any such method or methods. Iodine is quite expensive and the supply limited. Chlorine is the least expensive and most commercially available of all the halogens, and bromine is of especial value when the compounds are used in conjunction with lead anti-knock compounds. Iodine, and to some extent bromine, are also themselves effective as constituents in antiknock compounds.

As the exact manner in which my solvent constituents act upon the carbon deposit is not entirely understood, I do not intend my invention to be restricted by any explanation or theory. However, the two types of solvents mutually aid one another in attacking the gummy carbon binders, for it has been found that the effectiveness of their joint action is more than the cumulative effect of the two when used separately.

The substitution of halogen in an organic compound lowers the volatility without of necessity equivalent to tion modifies the eflectiveness of the composition. The halogen also aids in the removal of metal residues of-anti-knock constituents, andin some cases, has other desirable efiects.

The action of my new solvent composition may sometimes be improved by the use of a more or less complex mixture of one or both of the two causing solidification and thus enables the use of a number of the most effective types of solvents which would otherwise be too highly volatile at engine temperatures. The presence of the halogen in certain instances enhances the solvent action of the compounds and, therefore, makes available more efiective compounds. It also reduces the inflammability of the composition. It has been observed that the degree of halogenacomponents used. This complexity may result from (a) the production of a plurality of compounds obtained by the halogenation process, as, for example, the chlorination of diphenyl which is capable of producing a large number of chlorine-bearing compounds differing as to the number and location of the chlorine atoms in the molecule; or (b) the use of a product resulting from the halogenation of a complex organic material such as certain still fractions and solvent-extraction fractions obtained in the separations of petroleum products and coal-tar products.

It is of advantage to use a combination of materials which will have a fairly wide range of volatility, in order to have an appreciable proportion of the solvent present in both the liquid and vapor phases over a wide range of temperatures. This condition promotes the carrying of the solvent to all parts of the combustion chamber and the condensation of a sufiicient amount where needed. Itis additionally advantageous to use at least one component which has an extremely low vapor pressure at room temperature, preferably less than atmospheric pressure at a temperature of about 250 C. A mixture of the products obtained by chlorinating benzene until it contains an average of about two atoms of chlorine per molecule with the product obtained by chlorinating diphenyl ether until the average chlorine content is about six atoms per molecule is very effective in this manner. The more volatile portions of my solvent aid in carrying the less volatile portions to all parts of the combustion chamber and also condense during the compression stroke on the walls of the cylinder, cylinder head, piston head, valves, valve stems, etc. After the fuel has been exploded, there remains sufficient solvent to act effectively upon any carbon binder already deposited and inhibit the deposition of any more.

The relative proportions of halogenated oxygen-free organic constituents and oxygen-bearing organic constituents in the new solvent comprising my invention may vary within wide limits, depending upon the particular materials used, the kind of fuel to which the solvent is to be added, and the kind of engine employing the fuel, a very minor proportion of the more active components at times being quite effective. The ratio of the amount of halogenated oxygenfree organic constituents to the amount of oxygen-bearing organic material usually may vary from about one to ten, up to about ten to one, but preferably only from about one to two, up to two to one. For most applications a solvent comprising substantially equal amounts of each type has been found very satisfactory.

The amount of the solvent combination to be added to the fuel will depend upon the type of fuel and the type of engine using the fuel, and may vary over wide limits, for example, gener ally from about .001% to about .1% by weight based on the fuel. The amount will also depend upon the composition of the solvent and, for certain solvent compositions, less than .001% may be an efiective amount. The upper limit of the amount which may advantageously be mixed in the fuel is usually controlled by the effect of the added solvent on the carburetion ofthe fuel. When the solvent is largely composed of'high boiling (i. e., non-volatile) materials too large an amount will interfere withproper carburetion. when the solvent is principally composed of materials in the lower range of boiling points, e. g. 140 C. (i. e. of relatively 1 higher volatility), much larger amounts are permissible, for example up to-about 0.5%. In the average gasoline for use in the ignition type four-stroke gas engine, such as is usually eniployed in automobiles, the solvent should be present in the gasoline in an amount of from about .005% to about .05%.

A preferred amount for such conditions is about .0l%.

For use in heavier fuels and especially those employed in automotive and stationary Diesel engines, a larger amount is usually desirable,

- say from about .0l% to about .l% and preftively high surface temperatures in the combustion chamber, they should be particularly resistant to thermal decomposition and also, since it is an advantage for at least part of the solvent to exist in the vapor phase in the combustion chamber to facilitate proper distribution, the materials chosen should preferably be capable of distillation at atmospheric pressure without ap preciable decomposition.

Resistance to hydrolysis, although not essen-- tial, is a preferred characteristic, because of the tendency of moisture to condense on the walls of the cylinders, pistons. etc. when the en gine is operated at low temperatures or for short intervals. Under these conditions, easily hydrolyzed halogen compounds will tend to produce hydrogen halides which will cause corrosion of the internal parts of the engine and therefore the least corrosive compounds are generally des red for use in most types of engines.

The superiority of my engine fuel has been demonstrated commercially by its highly successful use in automobile, truck and bus engines In these cases, the solvent is mixed with the usual gasoline or heavier fuel before use. or may be directly iniected into the combust on chamber, or may be added by any other practicable means. More detailed methods are given below. An important application of my invention is to D esel engines where previously considerable difficulty has been met with in the form of carbon deposits which have militated against the more widespread use of this type of engine. The solvent constituents mav be added by any practicable means to the ordinary Diesel en ine fuel, much as in the case of soark-ienit on-ty'pe enzines. Many other specific applications of this invention have been made and will occur to those acouainted with the art. and this invention is intended to include all such ap lications. While it is contemplated that the solvent will be introduced into the engine by dissolving in, or mixing with the fuel, it may also be introduced into the engine in other ways, either undiluted, or diluted, or in the form of a suspension or emulsion in water. For example, either of the following means may be employed:

1. The solvent, preferably in the form of a vapor, mist, or spray, along with a small stream of air, is introduced into the combustion chamber, usually by admitting into the intake manifold.

2. The solvent is introduced, either directly into the combustion chamber or into the intake manifold, by means of some form of injector, usually mechanically actuated and preferably such as to produce a fine mist or spray.

The engine fuel according to my invention will then contain my new solvent comprising the combination of at least one representative of each of the types of compounds disclosed to inhibit the formation and aid in the removal of carbon deposits. It is usually preferably, but not absolutely necessary, that at least one of the solvents be of the aromatic series. The two components described have a cooperative dissolving eil'e'ct,

. lead in the lead each enabling the other to completely.

As the prior art, notably Midgley, would indicate, such a fuel is ideal when used in conjunction with an anti-knock compound such as tetraethyl lead since the organic halogen compounds are effective in pigmoting the conversion of the 0 de formed as a result mbustion into a lead halide which will be of tilo and therefore readily removed by the exhaust gases. Certain combinations of the materials contemplated also have the efiect of inhibiting the deleterious eflects of lead deposits.

Fuel containing iron or nickel carbonyl as an anti-rtlietogating agent will also b greatly improve w en compositions of th areA added thereto. 8 type described s previously indicated, it is among the ob ct of this invention to provide a metal-contai rfing anti-knock internal combustion en ine fuel having my solvent added thereto which will have the additional efiect of converting'the metal oxide formed into an easily removable product, and yet not causlng appreciable corrosion.

As specific examples of combinations of compounds which are within the scope of this invent1on and are desirable in use with anti-knock compounds such as tetra-ethyl lead are:

I. The combination of one or more brominated al phatic hydrocarbons such as butylene dibromlde, and amylene dibromide with:

II. The combination of one or more brominated aromatic hydrocarbons such as brominated benzene, brominated diphenyl, brominated naphthalene, brominated toluene, brominated ethyl benzene, with (a), (b), or (0) above.

For satisfactory results an excess of halogen must be present in order that the lead or other metal may be completely combined and efiectively removed. If this excess is present in the form of an easily hydrolyzed aliphatic compound, the unutilized portion may hydrolyze to some extent work more quickly and t causing appreciable corrosion. On th other hand, if no more than the amount of halogen needed to combine with the lead be present in the aliphatic compound and the excess halogen be present in an aromatic compound, then the unutilized excess will not hydrolyze and cause corrosion. If such carbon binder solvents as I have indicated above for use in metal containing engine fuels are utilized and the excess of halogen is present in an aromatic compound, then the efiect of this form of my new solvent will be both to inhibit carbon formation and also to aid in the removal of the metal in a most eflicient manner without causing corrosion. The advan tages of such a combined operative effect are obvious.

As previously indicated, my new solvent which I have broadly described is also suitable for use by itself and need not necessarily be added to a fuel. It may, for instance, be injected into an engine which is not running but preferably still hot. Then on starting it after a period of time, the released carbon will be removed by the exhaust gases. Other occasions for its use are apparent to those concerned with the removal of similar organic deposits.

Other modes of applying the principle of my invention may be employed instead of the one explained, change being made as regards the materials employed in carrying out the process, provided the ingredient or ingredients stated in any of the following claims or the equivalent of such stated ingredient or ingredients be employed.

I, therefore, particularly point out and distinctly claim as my invention:

1. As a composition of matter a normally liquid organic solvent comprising (a) a, halogenated aromatic monocyclic hydrocarbon and (b) a halogenated aromatic ether, said compounds having a vapor pressure below atmospheric at 170 C. and being sufficiently stable so as not to substantially decompose either when boiled at atmospheric pressure or under the conditions encountered in the combustion chamber of an internal combustion engine.

2. A composition in accordance with claim 1 in I which (a) is halogenated benzene. 

